At one time in society, it was virtually unnecessary to lock one's doors. Buildings and carriages were safe from general mischief except from a very small number of trouble makers. The later half of the twentieth century has seen a marked change in culture such that today, people lock their doors when they are within their homes and upon virtually every occasion of their leaving home. Likewise, travelers routinely lock the doors of their vehicles not only when they leave them but also while inside them. Security has become an issue and locks have abounded.
Typically a man will carry with him a house key, one or two car keys, an office key, a desk key, perhaps a bathroom key, and at least one other key entrusted to him by someone else. Around a business, numerous keys are used for everything from storage areas to conference areas to security areas to offices. The locksmith is a frequent visitor at some establishments to change out the locks or to open a lock for which no key can be found. Heretofore, it has been known to tag each key as with a disk attached by a string or wire and write thereon the identification of the associated lock. Alternatively, some have considered using plastic strips to color code the keys and locks. Of course, locksmiths have numbered their companion keys and locks for years. A need persists for a way to easily and uniformly identify a key to a lock.
In yet another aspect of the background of this invention, the key or key chain has become the universal constant which all members of society are likely to carry with them. A driver of a vehicle cannot generally operate the vehicle without a key and a latchkey kid going home from school alone cannot get into his own home without a key. The proliferation of locks has made the key the single most commonly carried personal article. Yet, one key looks like another of the same manufacturer and if the owner is unable to identify his key it is unlikely that any one else can do so. To solve this at least one organization has provided its members with metallic discs which fit on key rings and provide a national telephone number to assist in returning lost keys. Such programs are laudable, but they are of limited use when an emergency leaves the key owner unable to identify himself to authorities.